As rural and urban infrastructure continues to age and develop, there is a continual demand for cost-effective technologies relating to the construction and maintenance of highways, railways and the like. Often unappreciated but vitally important to the construction of such infrastructure is the underpass system. Underpass systems are typically designed to carry not only dead loads, but also live loads. While some of the most impressive underpass systems are used in mining or forestry applications where spans can exceed twenty (20) meters, they are also very common in regular highway construction to allow passage of railway, watercourses or other vehicular/pedestrian traffic. While concrete structures have been regularly employed for these purposes, such concrete structures are very expensive to install, cost prohibitive in remote areas, subject to strength weakening due to corrosion of the reinforcing metal, thereby requiring ongoing repair and are rigid limiting their use in certain environments.
In the field of overhead structures, such as for example but not limited to box culverts, circular and ovoid culverts, arch-type structures, encased concrete structures and other similar structures that make use of corrugated plate, there have been significant advances. For example, U.S. Pat. No. 5,118,218 to Musser et al. discloses a corrugated box culvert constructed from reinforced corrugated steel or aluminum sheets having very deep corrugations and a generally uniform bending moment profile for the whole length of the box culvert. By using significant material on the crown portions as well as on the haunch portions of the box culvert, significant loads can be carried by the box culvert. Ovoid and circular culvert structures are disclosed in U.K. Patent Application No. 2,140,848 where wing members are used to increase the load carrying capabilities of the culvert structures thereby to avoid bending of the crown portions of the culvert structures as live loads pass thereover.
U.S. Pat. No. 5,326,191 to Wilson et al. discloses a reinforced metal box culvert formed of interconnected corrugated metal sheets and having a crown, opposing sides and opposite curved haunches. Continuous corrugated metal sheet reinforcement is secured to at least the crown of the culvert and extends the length of the culvert which is effective in supporting the load. The metal sheet reinforcement has a profile which abuts the crown corrugations with the troughs of the metal sheet reinforcement being secured to the crests of the crown corrugations. The metal sheet reinforcement has a curvature complementary to the crown corrugations to facilitate securement. The metal sheet reinforcement enhances load carrying characteristics, reduces overburden requirements and allows the culvert to be used in large span applications.
U.S. Pat. No. 5,833,394 to McCavour et al. discloses a composite concrete reinforced corrugated metal arch-type structure comprising a first set of shaped corrugated metal plates interconnected in a manner to define a base arch structure with the corrugations extending transversely of the longitudinal length of the base arch structure and a second series of shaped corrugated metal plates interconnected in a manner to overlay the first set of interconnected metal plates of the base arch structure. The second series of metal plates has at least one corrugation extending transversely of the longitudinal length of the base arch structure with the troughs of the corrugations of the second series of metal plates secured to the crests of the first set of metal plates. The interconnected series of second metal plates and the first set of metal plates define individual, transversely extending, enclosed continuous cavities that are filled with concrete. The interior surfaces of the cavities for each of the first and second metal plates carry shear studs for providing a shear bond at the concrete-metal interface. The concrete filled cavities define curved beams transversing the base arch structure giving the base arch structure positive and negative bending resistance and combined bending and axial resistance to superimposed loads.
To provide resistance to deformation during construction of arch-type structures such as those discussed above, mechanically-stabilized earth construction techniques have been considered. For example, U.S. Pat. No. 4,618,283 to Hilfiker discloses an archway construction positioned over a pathway for supporting a crossroad or the like. The archway has three primary sections including an upper ceiling section which spans the pathway and which is supported on two vertical support sections positioned on opposite sides of the pathway. The three primary sections are each comprised of alternating layers of compacted soil fill and steel reinforcing mats, with the mats serving to stabilize the compacted soil fill. The ceiling section preferably includes at least three reinforcing mats, namely a lower flat mat and a pair of curved upper mats, with the three mats being separated by layers of compacted soil fill except in a central region midway between the vertical support sections where the three mats are connected together. The two upper curved mats of the ceiling section provide vertical support for the center of the lower flat mat.
U.S. Pat. No. 6,050,746 to McCavour et al. discloses a method for controlling deformation of an erected structural metal plate culvert or underpass during backfilling of the erected structure. The method comprises building progressively a reinforced earth retaining system on each side of the erected structure by alternately layering a plurality of compacted layers of earth with interposed layers of reinforcement to form reinforced earth on each side of the erected structure and securing each layer of reinforcement to its respective side of the structure. Securement of the layers of reinforcement to the sides of the erected structure controls deformation of the erected structure during backfilling. Each layer of reinforcement may be a plurality of strips extending away from the erected structure, or a reinforcement mat of interconnected rods.
In some instances such as for example in high load carrying environments, further reinforcement for overhead structures is required. To provide such further reinforcement, reinforcement ribbing secured to the exterior surface of the overhead structure has been considered. For example, FIG. 1a is an end view showing an archway 10 formed of interconnected corrugated metal plates or sheets. Reinforcement ribbing 14 is secured to the metal archway 10 at longitudinally spaced locations along the length of the metal archway 10. The reinforcement ribbing 14 at each location extends transversely of the longitudinal length of the metal archway 10. The reinforcement ribbing 14 at each location comprises, in this example, a plurality of reinforcement ribs 20 arranged end-to-end and extending along the crown portion and haunch portions of the metal archway 10.
FIGS. 1b and 1c show conventional reinforcement ribs 20. As can be seen, in each case the reinforcement rib 20 comprises a lower flange 30 having a curved undersurface 32 that rests on a crest of the metal archway 10. Fasteners (not shown) such as bolts pass through spaced holes in the lower flange 30 to secure the reinforcement rib 20 to the metal archway 10. An upstanding wall 34 intergral with the lower flange 30 runs the length of the lower flange. A head 36 is formed along the top of the upstanding wall 34. In the example of FIG. 1b, the head 36 is generally circular in cross-section and in FIG. 1c, the head 36 is generally rectangular in cross-section.
Although the reinforcement ribs 20 provide additional support, the reinforcement ribs are difficult to bend. Also, the reinforcement ribs 20 are typically formed using an extrusion process making the reinforcement ribs expensive to manufacture. Using extrusion also limits the size of the reinforcement ribs 20 that can be made. As will be appreciated, improvements in overhead structure reinforcement are desired.
It is therefore an object of the present invention at least to provide a novel reinforcement rib and overhead structure incorporating the same.